pubmed:abstractText |
The vascular endothelium, in response to pulsatile flow and vasoactive agents including acetylcholine, secretes the endothelium-derived relaxing factor (EDRF), a substance which regulates vascular tone. Recent interest in EDRF has focused on its possible dysfunction in atherosclerosis. In animal models of the disease, endothelium-dependent relaxation is markedly reduced. The continuous exposure of the endothelium in hyperlipidaemia to high concentrations of low-density lipoprotein (LDL), a known atherogenic risk factor, may explain this dysfunction. Here, we demonstrate that pathophysiological concentrations of LDL directly inhibit endothelium-dependent relaxation. Chemically modified LDL, in contrast, is inactive, implying that the inhibition is through a receptor-dependent mechanism.
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